The World Health Association and many governmental agencies recommend the wearing of facemasks by the general public to prevent the spread of COVID-19. It is believed that masks can significantly protect others and may offer some protection to the wearer. Although there are standards for FFRs, surgical masks, and recently for barrier face coverings, they all indicate the level of protection for the wearer. However, testing facial masks not at the point of inhalation, but at the source, the exhale, offers a new perspective on how to impede particle emissions. In this paper, the experimental results show that, although the barrier face covering is less effective than FFRs or surgical masks, it can reduce the concentration of aerosols downstream of the device. The results on barrier efficiency show a rapid decrease in effectiveness when the face covering is not sealed to the head. The barrier efficiency of two of the barrier face coverings tested is strongly dependent on leakage caused by the fit rather than the material. While some materials certainly are more effective than others in inhibiting particle penetration, an even more profound factor is the amount of leakage emitted from a mask. New approaches to fit and design in order to create a seal against leakage will become an important factor in combatting SARS-CoV-2.
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